Pipes in Indian Waste Water Treatment Industry

Have plastics eliminated the need for metal pipes?

Hello, I am doing research on pipes used in Indian Waste Water Treatment Industry and wanted to know which pipe materials are mostly used by the industry. It is my understanding that plastic pipes (PE, PPR, PVDF, ABS, CPVC and UPVC) are mostly preferred and galvanized iron pipes are not used. Is this understanding correct? Which of these plastics are mostly preferred? Are galvanized iron pipes still being used in some applications? Any response would be greatly appreciated.